Non-ionic surfactants have been known for many years. They are products used for detergency in many industrial applications. Non-ionic surfactants can be represented by the following structure:R—O—(CH2CH2O)x—H wherein x is generally 3-10 and R is generally C12 alkyl.
These materials are good detergents, but also result in copious foam during processing. In many applications areas, foam is undesirable, causing problems with process equipment. To add to the problem, many industrial processes are run at very high pH values. A condition, which improves cleaning and degreasing, but in many cases destroys the non-ionic.
Non-ionic surfactants of this type have what is referred to as a high cloud point.
Specifically, when one heats up a clear solution of the non-ionic, the solution becomes cloudy. This is attributed to the inability of the polyoxyalkylene group (—(CH2CH2O)x—) to hydrogen bind water. Once the high cloud point is reached, the ability to foam is destroyed, but detergency remains. Using a non-ionic at temperatures in excess of the cloud point of the non-ionic is one approach to controlling foam while still providing detergency. This approach does nothing to improve the alkaline stability of the molecule, since the chemical nature of the molecule itself has not been altered.
Additionally, the molecule may be modified to include polyoxypropylene groups onto the backbone.R—O—CH2CH2O)x—(CH2CH(CH3)O)yH wherein x is generally 3-10 and R is generally C12 alkyl and y ranges from 2 to 5. This alteration provides improvement to the alkali stability, but only marginally.Additional capping techniques have also been used. One approach is reaction with benzyl chloride resulting in the following structure;R—O—(CH2CH2O)x—CH2—C6H5 wherein C6H5 is benzyl. These compounds are good for alkali stability, however they contain aromatic groups, which are generally undesirable. Additionally these products are expensive to make.
Another approach is to use thionyl chloride to produce chloride capped non-ionic surfactants. This results in the following product;R—(OCH2CH2)xCl These materials have the best alkali stability, but are very expensive due to the expense and special requirements of reacting the thionyl chloride.
Non-ionic surfactants are used not only to provide detergency, but also to provide emulsification. One area in which this is important is emulsion polymerization. If standard non-ionic compounds are used to make the emulsion in which the polymerization occurs, they can provide a phenomenon called water blush. Anyone who has spilled water on inexpensive vinyl has seen a white deposit form. This deposit is the result of a blooming to the surface of the emulsifier. If one is able to provide a vinyl reactive group to the emulsifier, the emulsifier will become attached to the polymer and be unable to blush to the surface. Therefore, another aspect of the present invention is to provide vinyl capping non-ionic surfactants that will react with the polymer matrix in the emulsion polymerization reaction, providing polymers that do not water blush.
None of the compounds known to date provide the compounds of the present invention. These unique materials provide lower foam, alkali stability, and non-blush attributes, while being very efficient detergents and emulsifiers.